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Leaf switch buttons
Kremmit:
--- Quote from: MaximRecoil on August 14, 2006, 04:57:39 pm ---
--- Quote from: RayB on August 14, 2006, 04:14:38 pm ---Initially it sounded to me like the button was "bouncing" and a small gap, like already mentioned, would cause several contacts to be made with one press.
--- End quote ---
The worn switch actually had a slightly larger gap than the unworn switch I swapped with it, but about the same size gap as all the rest of the buttons' switches.
Maybe it was "bouncing"; I didn't even think of that. But if it was, it wasn't because the gap was too small. Maybe loss of tension in the leaves through excessive use over time could allow "bouncing" to happen?
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Maybe the bad contact was only making intermittent contact while the switch was closed; in effect, closing and opening and closing again in very rapid succession as the bad contact failed to provide a steady electron path even when the leaves were held together.
Wow, that's a long sentence.
MaximRecoil:
--- Quote from: Kremmit on August 18, 2006, 12:30:25 am ---Maybe the bad contact was only making intermittent contact while the switch was closed; in effect, closing and opening and closing again in very rapid succession as the bad contact failed to provide a steady electron path even when the leaves were held together.
Wow, that's a long sentence.
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I would say that you're right. I don't know why I didn't think of that. In fact, the night before I made this thread, that fire button stopped working briefly during the game. The next time I played it was working again, but of course, it was still doing multiple shots fired for one button press thing. I chalked it up to a fluke and didn't think of it again until now. So if the switch was worn enough that the button could be pressed and close the leaves but sometimes not close the circuit at all, then it follows that when the pressed button was closing the circuit that it was intermittent at best.
I was looking at it from the wrong angle, trying to figure out what could cause the leaves to physically make contact, lose contact, and make contact again so quickly; never considering that the actual circuit could be opening and closing with the leaves retaining physical contact all along, due to worn contact points.
bvicarious:
--- Quote from: MaximRecoil on August 14, 2006, 02:38:00 am ---I put a microswitch button in place of the leaf switch button and of course, it is always one shot per button press, which is the way it is supposed to be.
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I've been having the same exact problem with my microswitches! A single press will register multiple times, usually 2 or 3. They are in brand new condition and have hardly been used, and I had the same problem with my joystick microswitches until I got fed up and went optical.
I thought leafswitches would be more reliable since they're just pieces of metal connecting, so I was going to get some from ponyboy (http://forum.arcadecontrols.com/index.php?topic=36770.0), are these the ones you're using? I'm wondering if oxidation played any role in the malfunction, would one of these things help? - http://www.radioshack.com/product/index.jsp?productId=2104394
MaximRecoil:
--- Quote from: bvicarious on August 18, 2006, 10:02:04 am ---I've been having the same exact problem with my microswitches! A single press will register multiple times, usually 2 or 3. They are in brand new condition and have hardly been used, and I had the same problem with my joystick microswitches until I got fed up and went optical.
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I don't know what would cause that issue with microswitches, though I suppose they could have the same intermittent connection problems as a worn leaf switch. Seems unlikely with new microswitches though...maybe the quick disconnect tabs needed to be cleaned?
--- Quote ---I thought leafswitches would be more reliable since they're just pieces of metal connecting, so I was going to get some from ponyboy (http://forum.arcadecontrols.com/index.php?topic=36770.0), are these the ones you're using?
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No, the leaf switches I am using came stock on Ikari Warriors, Victory Road and probably other SNK machines of the time as well. They are nothing fancy; the contact points are nothing more than dimples pressed into the ends of the leaves.
--- Quote ---I'm wondering if oxidation played any role in the malfunction, would one of these things help? - http://www.radioshack.com/product/index.jsp?productId=2104394
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No doubt that dirty contact points could cause something like that. In my case, I'd cleaned all the contacts recently with isopropyl alcohol (91%) and they were plenty clean. All of the switches worked fine aside from that one. In this case I'd say that excessive wear of the contact points was the problem (the wear was very visible).
That pen should work fine if you have an oxidation problem, though you can accomplish the same thing with alcohol or a pencil eraser, or both.
Izrun:
If you're having problems with microswitches, I'm guessing it is bouncing. If you look at the picture below, that is a scope reading of a microswitch with a 5ms duration. As you can see, it transitions from connected to disconnected many times before staying constant. This is caused by the physics of any two surfaces. If you zoom in really close to pretty much anything, the surface is not truly smooth. The interaction of two non-smooth surfaces causes this phenomenom, called switch bouncing. There are many methods to debounce a switch (both physically using caps or buffers) or in software. What switch encoder are you using? It might be a mixture of you having a bad (really rough) microswitch and you software having two small a buffer.
Hope this helps.